Push-pull bar



United States Patent 3,411,747 PUSH-PULL BAR Charles H. Lister, Jr., 307 Park Blvd., Oldsmar, Fla. 33557, and James Eldred Jones, Sr., 3502 River Grove Drive, Tampa, Fla. 33610 Filed July 17, 1967, Ser. No. 653,707 3 Claims. (Cl. 254-1) ABSTRACT OF THE DISCLOSURE A bar whose length may be extended or shortened for the imposition of compression or tensile force on other objects, said changes in length being produced by the winding of a flexible cable upon a drum located within said bar. The drum is rotated by means of a ratchet wrench outside the bar.

This invention relates to devices for exerting a force between two opposing objects by extending a compression member or retracting a tension member placed between the opposing objects.

The most important application now known for this invention is for use in bracing rods used to lock into position heavy objects, as for example, automobiles, when placed for shipment in freight cars, highway trailers or ships.

Our invention is also applicable as a temporary support for concrete forms in the construction of buildings and large conduits. Also, for supporting insulating panels dividing refrigerator trucks or cold storage rooms into areas of different degrees of cold, and other places where a convenient prop or jack is needed.

There have been commercially available several types of devices for such applications as above described, utilizing wood columns and metal tubes. Such devices have utilized various arrangements of wedges and screws to produce an elongation thereof, and to lock the devices in extended position.

Our device provides a less expensive, more reliable and more convenient arrangement, utilizing a flexible cable and drum to produce the extending or retracting force.

The chief object of this invention is to provide a device as described which may quickly be extended with slight effort, and quickly released to its original length. An alternative device would act as a convenient mechanism for exerting a tensile force, commonly known as a come along.

Another object is to provide such a device where the frictional losses are low and the mechanical advantage is great.

Still further object will be apparent to one skilled in the art from a consideration of the following description and drawings which show a preferred embodiment.

In the drawings,

FIGURE 1 is a front view.

FIGURE 2 is a detailed longitudinal cross-section view of an end of the device incorporating the extension and locking mechanism.

FIGURE 3 is another longitudinal cross-section view taken at right angles to the plane of FIGURE 2.

In the drawings, where like numerals indicate similar parts a long tube is shown, having attached to one end 11 a shoe 12, which preferably is provided with a resilient pad 13. The other end 14 is open, and inserted therein in telescoping relationship is a tube 15, having an outside diameter slightly smaller than the inside diameter of tube 10. Tube 15 has at its outer end 16 a shoe 17 which may be similar to shoe 12.

In certain conditions telescoping channels would be preferable to the cylindrical tubes shown in the drawings. When the device is to be used in tension, shoes 12 and 17 ice will obviously be replaced with hooks, not shown in the drawings.

The inner end 18 of tube 15 is provided with a collar 19 through which is passed a transverse pin 20 for connection to a flexible wire cable 21.

A hole 22 is provided transverse of tube 10 adjacent end 14. Through hole 22 is rotatably fitted drum shaft 23, which extends beyond tube 14 a distance suflicient to mount thereon two conventional ratchet wrench handles 24, 25. Handles 24, 25 are keyed to shaft 23 by a square cross-section or other conventional means.

Washers 26, 27 and lock pins 28, 29 are provided to prevent axial movement of drum shaft 23 relative to tube 14.

Drum 30 is mounted on shaft 23 for rotation therewith, and is proportioned to fit inside tube 15.

Flexible wire cable 21 is attached to drum 30, preferably by looping it around a pin 31 above a flange 32 of drum 30. The loose ends of cable 21 are passed around pin 20 and fastened each end to the other with conventional cable connectors 32.

A pair of longitudinal slots 33 are provided in tube 15 to provide clearance for shaft 23, to permit axial movement of tube 15 inside tube 14.

A wrench handle locking collar 34 is slidably fitted around tube 10, having a recess 35 parallel to the axis of tubes 10, 15, and proportioned to slide over insde wrench handle 24 when said handle is positioned parallel to said axes.

In the operation of our device it is placed horizontally, vertically or at an inclined position between two objects, as for example the end wall of a freight car and the bumper of an automobile.

The device is then extended by locking wrench handle 24 in position with collar 34, and rotating drum 30 by means of Wrench handle 25.

As drum 30 rotates, cable 21 is wound thereon, developing a tension in cable 21 which draws pin 20 and collar 19 toward the drum 30. This slides tube 15 outwardly from tube 10, increasing the distance between shoes 12 and 17 and thereby creating a spreading force between the objects (the freight car wall and automobile bumper in our example) contacting said shoes.

The provision of ratchet wrench handle 24 prevents drum 30 from unwinding when the operator releases his force on handle 25. Handle 25 is most conveniently made of the same commercially available ratchet type as handle 24, but our device would function if only handle 24 is of the ratchet type.

Tension in cable 21 causes handle 24 to tend to rotate. R'otation is prevented by collar 34. Friction between handle 24- and collar 34 is adequate to effectively prevent disengagement of these parts, even when subjected to vibration over long periods of time. This friction is released when it is desired to shorten my jack by temporarily pressing on handle 25.

It is obvious that with our device a substantial elongation, up to several feet in length is possible, if slots 33 and cable 21 are made long enough.

The end 11 may be provided with conventional means for making large adjustments in length, by providing a telescoping arrangement of tubes, a series of axially spaced holes in each tube, and a bolt passing through any pair of holes which provides the desired initial length.

It is obvious that drum shaft 23 could alternatingly be mounted in tube 15 instead of tube 10 if pin 20 were attached to tube 10 instead of tube 15, as heretofore described.

The use of our device therefore provides not only the function of locking a heavy object in a desired position, but also makes it possible to force the heavy object to the exact desired final position, if it has been only approximately positioned earlier.

When it is desired to release the device, locking collar 34 is moved axially away from handle 24. This permits handle 24 to rotate, along with shaft 23 and drum 30. This releases the tension on cable 21 and permits collar 19 and tube 15 to retract axially within tube 10, thereby shortening the distance between shoe 12 and 17, and releasing the force between the locked objects (as for example the freight car wall and automobile bumper).

Such releasing action can obviously be accomplished with almost no time or energy, as opposed to the laborious unscrewing of conventional screw jacks.

While we have described our invention by illustration of a preferred embodiment, certain modifications will be apparent to one skilled in the art, and we intend to be restricted only within the scope of the claims.

We claim as our invention:

1. In a device for imposing compression or tensile forces on other objects, a pair of longitudinal elements in telescopic relationship to each other, a flexible element attached to one of said longitudinal elements, and a portioned to selectively restrict the rotation of said ratchet Wrench.

2. In the device of claim 1, wherein the axle of said drum is perpendicular to the axes of said longitudinal elements and extends outwardly of said longitudinal elements, said axle being rotated by a first conventional ratchet wrench mounted upon the portion of said axle extending outwardly of said longitudinal elements, and a collar surrounding said longitudinal elements, said collar movable axially of said longitudinal elements and being proportioned to selectively restrict the rotation of said ratchet wrench, and a second ratchet wrench mounted on said axle exterior to said collar for the release of pressure between said collar and said first ratchet wrench during the axial adjustment of said collar.

3. In the device of claim 1, wherein the axle of said drum is perpendicular to the axes of said longitudinal elements and extends outwardly of said longitudinal elements, and a pair of longitudinal slots in that longitudinal element to which the flexible element is fastened, proportioned to permit sliding movement of said axle in said slots.

References Cited UNITED STATES PATENTS 3,196,991 7/1965 Johnson et al. 287-58 X FOREIGN PATENTS 272,491 4/ 1914 Germany. 1,164,334 2/1964 Germany.

MILTON S. MEHR, Primary Examiner. 

